     (s/optional-key :type)
     (describe [v/IndicatorType]
               "Specifies the type or types for this Indicator")
+
+    (s/optional-key :tags)
+    (describe [s/Str]
+              "Descriptors for this indicator")
 
     (s/optional-key :observable)
     (describe c/Observable

              "Test Mechanisms effective at identifying the cyber Observables specified in this cyber threat Indicator")

    ;; Extension fields:
    :producer s/Str
    (s/optional-key :specifications) [(s/conditional
                                       #(= "Judgement" (:type %)) JudgementSpecification
                                       #(= "ThreatBrain" (:type %)) ThreatBrainSpecification

(s/defschema ThreatBrainSpecification
  "An indicator which runs in threatbrain..."
  {:type (s/eq "ThreatBrain")
   (s/optional-key :query) s/Str
   :variables [s/Str] })

(s/defschema SnortSpecification
